GLACIERS OF PASSAGE CANAL AND BLACKSTONE BAY 363 miles,1 though the isthmus is only 10J miles wide in a straight line. Davidson has proposed that this be called Whidbey Isthmus.2 There is also at difficult, roundabout, non-glacial route from the delta of Cabin Creek, on Passage Canal, through a series of valleys to the north of Portage Glacier to Cook Inlet. This route was traversed by army parties in 1898 and 1899. Along it there are several small ice tongues, shown on maps by Kelly and Herron, but not otherwise described. Portage Glacier. Portage Glacier, as described by Petroff, Mendenhall, Learnard, and Castner, is fed from snowfields that lie to the north and south of the pass. There are three tributaries from the southern side and one or two from the northern, which unite to form an east-west trending glacier between 4 and 5 miles long, J to ^ mile wide, and with the part flowing westward toward Turnagain Arm much the longer. The divide in this saddle-like glacier is about a mile from the eastern terminus at an elevation of between 1000 and 1100 feet, and both divisions of the glacier slope moderately, excepting at the divide, which has a steep slope on the eastern side. Each terminus lies almost at sea level, though some distance back from it. Portage Glacier is best shown upon the army officer's 1898 map and upon the map made in 1909 by Grant and Higgins (Fig. 51). It is also shown, less in detail, on the 1898 map published by Mendenhall and copied on Hamilton's map,8 and on a second U. S. Geological Survey map 4 where the eastern terminus of Portage Glacier is shown incorrectly as a tidal glacier ending in Passage Canal. This error has also been followed in a Coast Survey chart. Advance of Portage Glacier. When Lieutenant Whidbey arrived at the head of Passage Canal on June 7, 1794, Vancouver states that he found that he "had approached within twelve miles in a direction S. 60 W. of the spot where . . . (he) had ended his examination of Turnagain Arm. The intermediate space was an isthmus so frequently alluded to before, on either side of which the country was composed of what appeared to be lofty, barren, impassable mountains, enveloped in perpetual snow; but the isthmus itself was a valley of some breadth, which, though it contained elevated land, was very free from snow, and appeared to be perfectly easy of access; a little to the eastward of thig valley, a rapid stream of fresh water 5 rushed down a gully in the lofty mountains, and found its way to the sea through a margin of low land extending from the base of the mountains, and producing pine trees, cranberries and a few other shrubs. On the western point of entrance into this brook was a small house. . . . This house and the general appearance of the country removed every doubt of their situation being then on the eastern side of that pass, by which the Russians maintain a communication between their settlements in these two extensive inlets. Mr. Whidbey, however, for his further satisfaction, was very desirous of finding the road or path by which the intercourse was carried on; and although he was unsuccessful in ascertaining this, yet it did not appear to him that any particular track was necessary, as lTarr, R. S. and Martin, Lawrence, Annals Assoc. Amer, Geographers, Vol. IL 1912, pp. 88-39 and Fig. 1 on p. 27. * Davidson, George, Op. cit., p. 24. * PI. H in Bull. 277, U. S. Geol. Survey, 1906. « PI. I in Bull. 327, U. S. Geol. Survey, 1907; see also Coast and Geod. Survey, Chart 8550, 1909. * Cabin Creek, the largest stream from Billings Glacier.